CN1781601B - A shaped body and its use as catalyst - Google Patents

Abstract

A method for producing a shaped body, consisting of at least one porous oxide material, preferably a titanium silicate, and at least one metal oxide, comprising the following step (i): (i) the porous oxide material is mixed with at least one metal oxide sol, preferably a silica sol, that has a low alkaline and alkaline-earth metal ion content and/or with at least one metal oxide that has a low alkaline and alkaline-earth metal ion content. The invention also relates to the use of said shaped body in the production of an alkene oxide.

Description

Shaped bodies and their use as catalysts

This application is a divisional application of the divisional application entitled "Method for Producing Molded Body Using Metal Oxide Sol" filed on March 10, 2004 with application number 200410008075.0 (application date is April 7, 1999).

technical field

The invention relates to: a process for producing a shaped body comprising at least 1 porous oxidic material and at least 1 metal oxide; the shaped body itself; and its reaction as an organic compound, in particular with at least 1 carbon-carbon double Application of catalysts in epoxidation reactions of bonded organic compounds.

Background technique

Shaped bodies comprising porous oxide materials are used in a variety of chemical processes. Therefore, there is a need for a production method for producing shaped bodies in quantities meeting industrial requirements at low cost.

To produce shaped bodies, the porous oxidic material is usually mixed with binders, organic tackifying substances and liquids in order to form the mixture into a paste, which is then compacted in a kneader or disc mill. Subsequently, the mass obtained is shaped by means of a piston extruder or a screw extruder, and finally the shaped body obtained is dried and calcined.

In order for the produced shaped bodies to be suitable again for the production of very reactive products, chemically inert binders which prevent further reaction of such products are required.

Suitable binders are a range of metal oxides. Examples which may be mentioned are oxides of silicon, aluminium, titanium or zirconium. Silica as binder is disclosed, for example, in US 5,500,199 and US 4,859,785.

In such binders, the content of alkali and alkaline earth metal ions should be as low as possible, and as such, it is desirable to use a binder source that contains little or no alkali and alkaline earth metals.

For the production of the aforementioned metal oxide binders, corresponding metal oxide sols can be used as starting materials. In the preparation of, for example, the above silica binder containing little or no alkali metal and alkaline earth metal, silica sol containing little or no alkali metal and alkaline earth metal is used as a binder source.

In the preparation of silica sols it is possible to start from alkali metal silicates, but this usually leads to an unacceptably high content of alkali metal ions in the silica sol. The preparation of such silica sols is described, for example, in Ullmann's Encyclopedia of Industrial Chemistry, vol. A23 (1993), pp. 614-629.

JP-A-07 048 117 discloses a process for the preparation of silica sols by hydrolysis of alkoxysilanes with ammonia in the presence of a large excess of alcohol; the silica sols obtained contain up to 10% by weight of silica.

JP-A-05 085 714 describes a process for the acid decomposition of alkoxysilanes, likewise in an alcoholic medium. The silicon dioxide content of the silica sol produced by the method is 1-10wt%.

A disadvantage of the silica sol preparation methods disclosed in the latter two publications is that the achievable silica content of the silica sols is too low. This makes the process uneconomical, since the capacity of the plant is wasted with large amounts of water in the sol production and further processing.

Contents of the invention

It is an object of the present invention to provide an industrially applicable process for the production of shaped bodies which are low in alkali metal and alkaline earth metal ions and which can be used as catalysts, preferably in fixed beds.

We have found that this object can be achieved by a method for producing such shaped bodies: the porous oxidic material is mixed with a metal oxide sol and/or a metal oxide in a first step of the method, wherein the metal oxide sol and The metal oxides each have a low content of alkali metal and alkaline earth metal ions.

In summary, the present invention provides a method for producing a shaped body comprising at least one porous oxidic material and at least one metal oxide, comprising the following step (i):

(i) One or more porous oxidic materials are mixed with at least one metal oxide sol low in alkali metal and alkaline earth metal ions and/or at least one metal oxide low in alkali metal and alkaline earth metal ions.

The invention also provides a shaped body which can be produced by the method described above and which preferably has an alkali metal and alkaline earth metal ion content of less than 700 ppm, particularly preferably less than 600 ppm, in particular less than 500 ppm.

In a preferred embodiment of the process according to the invention, the metal oxide sol is prepared by hydrolysis of at least one metallic acid ester.

Accordingly, the present invention also provides such a process as described above, wherein the metal oxide sol is prepared by hydrolysis of at least one metal acid ester.

Metal acid esters used for hydrolysis may be purified prior to hydrolysis. All suitable methods are conceivable here. Preference is given to subjecting the metal acid ester to distillation prior to hydrolysis.

With regard to the hydrolysis of the metal esters, in principle all possible methods can be used. In the process of the invention, however, the hydrolysis is preferably carried out in an aqueous medium. The advantage of this is that much less alcohol needs to be distilled off compared to known hydrolysis methods using excess alcohol such as JP07,048,117 or JP05,085,714.

The hydrolysis reaction can be catalyzed by adding basic and acidic substances. Preference is given to those basic or acidic substances which can be removed by calcination without leaving residues. It is especially preferred to use substances selected from the group consisting of ammonia, alkylamines, alkanolamines, arylamines, carboxylic acids, nitric acid and hydrochloric acid. Particular preference is given to using ammonia, alkylamines, alkanolamines and carboxylic acids.

The metal acid esters used in the process of the invention are preferably orthosilicates.

In the method of the present invention, the implementation conditions of metal ester hydrolysis are: temperature, 20-100°C, preferably 60-95°C; pH value, 4-10, preferably 5-9, especially preferably 7-9.

The molar ratio of catalytically active substance/metal acid ester is generally 0.0001-0.11, preferably 0.0002-0.01, especially 0.0005-0.008.

In the process of the invention, the hydrolysis reaction produces a metal oxide sol, preferably a silica sol, having an alkali metal and alkaline earth metal ion content of less than 800 ppm, preferably less than 600 ppm, more preferably less than 400 ppm, more preferably less than 200 ppm, more preferably less than 100 ppm, especially preferably Less than 50 ppm, more particularly preferably less than 10 ppm, especially less than 5 ppm.

Accordingly, the present invention provides a metal oxide sol which has an alkali metal and alkaline earth metal ion content of less than 800 ppm and which can be prepared by hydrolysis of at least one metal acid ester.

The metal oxide content of the metal oxide sol prepared by the method of the present invention is generally at most 50 wt%, preferably 10-40 wt%.

The alcohol formed in the hydrolysis is usually distilled off during the process of the invention. However, small amounts of alcohols are also permissible to remain in the metal oxide sol, provided they do not have a negative influence on the subsequent steps of the process according to the invention.

The industrial use of the metal oxide sols prepared by the process according to the invention has the advantage that they show no tendency to form gels. Therefore, it becomes superfluous to take special precautions against gel formation. The metal oxide sols prepared by the process according to the invention can be stored for several weeks, which makes the timing of their preparation in further processing steps unproblematic.

In the process of the present invention, the mixture comprising at least one porous oxidic material and at least one metal oxide is prepared using the metal oxide sol prepared as described above as the metal oxide source.

In principle, the method of production of the mixture is not subject to any restrictions. However, the method of the invention preferably employs the method of spraying a suspension comprising at least one porous oxidic material and a metal oxide sol.

Here, the content of porous oxidic material present in the suspension is not subject to any restrictions, as long as the suspension is processable and sprayable during production. The weight ratio of the porous oxide material to the metal oxide of the metal oxide sol is preferably 10-0.1, especially preferably 8-1.

The main components of the suspension are generally porous oxide material, metal oxide sol and water. The suspension may additionally contain residual traces of organic compounds. They may arise, for example, from the preparation of porous oxidic materials. Likewise, alcohols formed in the hydrolysis of the metal esters or, as mentioned above, substances added to facilitate the hydrolysis of the metal esters are also conceivable.

Depending on the moisture content of the mixture required for further processing, subsequent drying may take place. Here, all conceivable methods can be used. The drying of the mixture is preferably carried out simultaneously with the spraying in the spray drying step. The spray dryer is preferably operated with an inert gas, especially preferably nitrogen or argon.

As regards the porous oxidic materials which can be used for the production of the shaped bodies by the process according to the invention, there are no specific restrictions, provided that the shaped bodies described herein can be produced from these materials and as long as these materials have the necessary catalytic activity.

The porous oxidic material is preferably a zeolite. Zeolites are well known as a class of crystalline aluminosilicates with ordered channels and cage structures containing micropores. For the purposes of the present invention, the term "micropore" corresponds to the definition in "Pure Applied Chemistry" 57 (1985), p. 603-619 and refers to pores with a diameter of less than 2 nm. The framework of this zeolite is composed of SiO ₄ and AlO ₄ tetrahedra connected by sharing oxygen atoms. An overview of such known structures can be found, for example, in WM Meier, DH Olson and Ch. Baerlocher, "Atlas of Zeolite Structure Types", Elsevier, 4th edition, London 1996.

There are also classes of zeolites which do not contain aluminum and where the Si(IV) in the silicate lattice is partially replaced by titanium in the form of Ti(IV). Such titanium zeolites, especially those with a crystal structure of the MFI type, and their possible preparation are described, for example, in EP-A0 311983 and EP-A0 405 978. Besides silicon and titanium, such materials may additionally contain elements such as aluminum, zirconium, tin, iron, niobium, cobalt, nickel, gallium, boron or small amounts of fluorine.

In the described zeolites, titanium may be partially or completely replaced by vanadium, zirconium, chromium, niobium or iron or mixtures of two or more of them. The molar ratio of titanium and/or vanadium, zirconium, chromium, niobium or iron to the sum of silicon and titanium and/or vanadium, zirconium, chromium, niobium or iron is generally 0.01:1-0.1:1.

Titanium zeolites with MFI structure are known to be identified by specific X-ray diffraction patterns, and can also be identified by means of lattice vibration bands in the infrared (IR) region around 960 ^cm Crystalline and amorphous titanium dioxide phases are distinguished.

Preference is given to using titanium, vanadium, chromium, niobium or zirconium zeolites, more preferably titanium zeolites, especially titanium silicalites.

Specific examples are titanium, vanadium, chromium, niobium and zirconium zeolites having a pentasil zeolite structure, in particular the following types designated by X-ray crystallography: BEA, MOR, TON, MTW, FER, MFI, MEL, CHA , ERI, RHO, GIS, BOG, NON, EMT, HEU, KFI, FAU, DDR, MTT, RUT, RTH, LTL, MAZ, GME, NES, OFF, SGT, EUO, MFS, MWW or MFI/MEL structures and ITQ-4. Zeolites of this type are described, for example, in the aforementioned Meier et al. It is also conceivable to employ titanium-containing zeolites having the structure UTD-1, CIT-1 or CIT-5 in the process of the invention. Other titanium-containing zeolites are those having the structure ZSM-48 or ZSM-12.

Such zeolites are described inter alia in US-A 5 430 000 and WO 94/29408, the contents of which are hereby incorporated by reference in their entirety in relation to the subject matter herein. In the process according to the invention, it is especially preferred to use titanium zeolites having the structure MFI, MEL or MFI/MEL.

Also preferred are, in particular, titanium-containing zeolite catalysts commonly referred to as "TS-1", "TS-2", "TS-3", and titanium zeolites having an isomorphic framework structure with beta-zeolite.

Accordingly, the present invention provides a method for producing a shaped body as described above, wherein the porous oxidic material is a zeolite.

Of course, it is also possible to use mixtures of 2 or more porous oxidic materials, especially those mentioned above, in the process of the invention.

The above-mentioned titanium, zirconium, chromium, niobium, iron and vanadium zeolites are usually prepared by combining a metal oxide source, preferably a silica source, with a titanium, zirconium, chromium, niobium, iron or vanadium source, such as titanium oxide or a suitable An aqueous mixture of vanadium oxide, zirconium alkoxide, chromium oxide, niobium oxide or iron oxide, and as a sample a nitrogen-containing organic base such as tetrapropylammonium hydroxide, if desired with the addition of a basic compound, in a pressure vessel at high temperature The reaction takes hours or days to form a crystalline product. It is filtered, washed, dried and calcined at high temperature to remove organic nitrogen bases. In the powder thus obtained, at least a part of titanium or zirconium, chromium, niobium, iron and/or vanadium is present in different proportions in 4-, 5- or 6-coordination (number) in the zeolite framework. To improve the catalytic performance, the product can then be washed repeatedly with sulfuric acid acidified hydrogen peroxide solution, after which the titanium or zirconium, chromium, niobium, iron and/or vanadium zeolite powder must be dried and calcined again. The titanium or zirconium, chromium, niobium, iron or vanadium zeolite powders thus prepared can be used in the process of the invention as constituents of the aforementioned suspensions.

Thus, in particular, the present invention provides a method as described above, wherein one or more porous oxidic materials are mixed with at least one metal oxide sol, wherein the one or more porous oxidic materials are obtained by comprising Prepared by one or more steps in steps (a) to (f):

(a) preparing a preferably aqueous mixture of at least one metal oxide source, preferably a silica source, with another metal source, for example a source of titanium, zirconium, chromium, niobium, iron or vanadium,

(b) crystallization of the mixture from (a) in a pressure vessel to which at least 1 template compound and, if desired, another basic compound are added,

(c) drying of the crystalline product present in the suspension from (b), preferably by spray drying,

(d) calcining the dried product from (c),

(e) the calcined product from (d) is comminuted, for example by grinding, so as to have a particle size of less than 500 μm, preferably less than 300 μm, especially preferably less than 200 μm,

(f) If desired, the pulverized product from (e) is repeatedly washed, subsequently dried and calcined.

There is also no restriction on the pore structure of the porous oxide material, i.e. the material may have micropores, mesopores, macropores, micropores and mesopores, micropores and macropores, mesopores and macropores or micropores, Mesopores and macropores, wherein the definitions of the terms "medium pores" and "macropores" also correspond to the definitions in the aforementioned document "Pure Applied Chemistry", referring to pores with diameters greater than 2 nm to about 50 nm and greater than about 50 nm, respectively.

However, it is preferred to use a microporous oxidic material, such as titanium silicate.

In another preferred embodiment of the process according to the invention, one or more porous oxidic materials are mixed in step (i) with at least one metal oxide low in alkali metal and alkaline earth metal ions.

If the porous oxidic material is mixed with 2 or more metal oxides, it is possible to first mix the 1 or more porous oxidic materials with 1 metal oxide and then mix the obtained mixture with another metal oxide . This mixture can then be mixed with another metal oxide if desired. Likewise, the porous oxide material can also be mixed with a mixture of 2 or more metal oxides.

The content of alkali and alkaline earth metals in the metal oxide or the mixture of 2 or more metal oxides is generally less than 800 ppm, preferably less than 600 ppm, especially preferably less than 500 ppm, especially less than 200 ppm.

Such metal oxides low in alkali metal and alkaline earth metal ions are, for example, pyrogenic (pyrogenic) metal oxides, such as pyrogenic silica.

Of course, conventional metal oxides may also be used in the process of the invention, provided their alkali and alkaline earth metal ion contents are suitably low, as indicated above.

It is also possible to reduce the content of alkali metal and alkaline earth metal ions in one or more traditional metal oxides, if the content of alkali metal and alkaline earth metal ions is higher than the above-mentioned conditions, by washing, extraction or other appropriate measures, and of course A combination of two or more suitable measures may be used to purify the metal oxides to a level usable in the process of the invention.

Depending on the measures taken to reduce the content of alkali metal and alkaline earth metal ions, appropriate post-treatment of one or more traditional metal oxides may be required. For example, if the alkali metal and alkaline earth metal ion content of the conventional metal oxide is reduced by washing, it is sometimes necessary to dry the conventional metal oxide after washing and then mix it with one or more porous oxide materials.

In the method of the present invention, of course, the mixture obtained by mixing one or more porous oxidic materials and metal oxides can be mixed with at least one metal oxide sol with low content of alkali metal and alkaline earth metal ions. In principle, no limitation is imposed on the method of preparation of such a mixture, as in the preparation of the mixture of porous oxide material and metal oxide sol described above. However, it is preferred that the suspension comprising a mixture of one or more porous oxidic materials and one or more metal oxides, and one or more metal oxide sols is sprayed. As regards the content of porous oxidic material present in the suspension, there are no restrictions as long as, as already described above, the processability of the suspension is ensured.

Furthermore, of course, in the method of the present invention, the mixture formed by mixing at least one porous oxide material with at least one metal oxide sol is mixed with at least one metal oxide with low content of alkali metal and alkaline earth metal ions. mix. Here, the mixing with one or more oxides may be performed immediately after the preparation of the mixture of one or more porous oxide materials and one or more metal oxide sols. As already described above, if drying is required after the preparation of the mixture of one or more porous oxide materials and one or more metal oxide sols, the metal oxides can also be mixed with the dried mixture .

In the process according to the invention, it is likewise possible to simultaneously mix one or more porous oxidic materials with at least one metal oxide sol and with at least one metal oxide.

The mixture obtained after passing through one of the above-mentioned embodiments of the invention is compacted in a further stage of the process according to the invention. During this compacting or shaping step, if desired, additional metal oxides may be introduced, the metal oxide sols prepared as described above may be used as their metal oxide sources. This processing step can be carried out in any suitable equipment, but kneaders, disc mills or extruders are preferred. As an industrial application of the method according to the invention, disk mills are particularly preferred.

If, according to the embodiments already described above, first a mixture of at least 1 porous oxidic material and at least 1 metal oxide is prepared, the mixture is then compacted and a low alkali metal content is additionally added in this compaction step And the metal oxide sol of alkaline earth metal ions, in the preferred solution of the present invention, use 20-80wt% porous oxide material, 10-60wt% metal oxide and 5-30wt% metal oxide sol. It is especially preferred to use 40-70 wt% porous oxide material, 15-30 wt% metal oxide and 10-25 wt% metal oxide sol. These weight percentages refer in each case to the final resulting shaped body as described below. Preference is given here to using porous oxidic titanium-containing materials and silica sols.

In another embodiment of the method of the present invention, the mixing of one or more porous oxidic materials with one or more metal oxides low in alkali metal and alkaline earth metal ions is carried out during the compaction step. Thus, in this compaction step, it is also possible that one or more porous oxidic materials, one or more metal oxides and additionally at least one metal oxide sol are mixed.

During this shaping step, one or more tackifying substances may also be added as materials for converting the mixture into a paste; these substances are especially useful for increasing the stability of the uncalcined shaped body as will be described below. For this purpose, any suitable substance known from the prior art may be used. In the process of the present invention, water, or a mixture of water and one or more water-miscible organic substances is used in order to convert said mixture into a paste. The material used to convert the mixture into a paste can be removed again during the subsequent calcination of the shaped body.

Preference is given to using organic, especially hydrophilic, organic polymers such as cellulose, cellulose derivatives such as methylcellulose, ethylcellulose or hexylcellulose, polyvinylpyrrolidone, ammonium (meth)acrylate, Tylose, Or a mixture of 2 or more of them. Especially preferred is the use of methylcellulose.

As a further additive, ammonium, amine or amine-like compounds, such as tetraalkylammonium compounds or amino alkoxides, can be added. This other additive is described in EP-A0 389 041, EP-A0200 260 and WO95/19222, the contents of which are incorporated herein by reference in their entirety.

Instead of basic additives, acidic additives can also be used. Preference is given to using those organic acidic compounds which can be burned off by calcination after the shaping step. Carboxylic acids are especially preferred.

The amount of such additives is preferably 1-10 wt %, especially preferably 2-7 wt %, based on the finally produced shaped body to be described below.

In order to influence the properties of shaped bodies such as transport pore volume, transport pore diameter and transport pore distribution, further substances, preferably organic compounds, especially organic polymers, can be added as agents which can also influence the formability of the composition. further additives. Such additives include, alginate, polyvinylpyrrolidone, starch, cellulose, polyether, polyester, polyamide, polyamine, polyimine, polyalkene, polystyrene, styrene copolymer, polyacrylic acid esters, polymethacrylates, fatty acids such as stearic acid, high molecular weight poly(alkylene) glycols such as polyethylene glycol, polypropylene glycol or polytetramethylene glycol, or mixtures of two or more thereof. The total amount of these materials used is preferably 0.5-10 wt%, especially preferably 1-6 wt%, based on the final formed body described below.

The present invention therefore also provides the use of poly(alkylene)glycols, in particular polyethylene glycols, for the production of titanium silicate-containing shaped bodies, in particular those useful as selective oxidation catalysts.

In a preferred embodiment, the process according to the invention is used to produce shaped bodies which are essentially microporous but which may additionally have mesopores and/or macropores. The pore volume of the mesopores and macropores in the molded body of the present invention, measured according to DIN66133, mercury porosimetry, is greater than 0.1ml/g, preferably greater than 0.2ml/g, especially preferably greater than 0.3ml/g, especially greater than 0.5ml/g .

The order in which the above-mentioned additives are added to the mixture obtained by one of the above-mentioned methods is not critical. The other metal oxides are introduced first in the form of a metal oxide sol, followed by the adhesion-promoting substance, followed by the substance affecting the transportability and/or formability of the compacted composition, or in any other desired order, all equally possible.

Before compaction, the still largely powdery mixture is, if desired, homogenized in a kneader or extruder for 10 to 180 minutes. This step is generally carried out at a temperature in the range of about 10°C to the boiling point of the materials used to convert the mixture into a paste, and at atmospheric pressure or superatmospheric pressure. The mixture is kneaded until an extrudable mass is formed.

In the process according to the invention, the composition obtained from the compaction step, which is now ready for shaping, has a metal oxide content, based on the total composition, of at least 10% by weight, preferably at least 15% by weight, especially preferably at least 20% by weight %, especially at least 30 wt%. In particular, when titanium-containing microporous oxides are used, the compositions produced according to the method of the present invention do not suffer from thixotropic properties in the subsequent forming steps.

In principle, the kneading and shaping can be carried out using any conventional kneading and shaping apparatus and methods known from the prior art which are suitable for producing eg shaped catalyst bodies.

In the method preferably employed, shaping is effected by extrusion in customary extruders, the extrudates produced having, for example, a diameter in general from about 1 to about 10 mm, especially from about 1.5 to about 5 mm. Such extrusion devices are described, for example, in Ullmann's Encyclopedia of Industrial Chemistry, 4th Edition, Vol. 2 (1972), p. 295 et seq. In addition to the possibility of using screw extruders, preference is likewise given to using piston extruders. In large-scale industrial applications of the process, screw extruders are especially preferred.

The extrudates can be extruded rods or honeycombs. The honeycomb body can have any desired shape. For example, they may be round extrudates, hollow extrudates or star-shaped extrudates. The honeycomb body can also have any diameter. Its shape and diameter generally depend on the machining engineering requirements, that is to say on the machining process in which the shaped body is to be used.

Precious metals may be applied to the material in the form of suitable precious metal components, for example in the form of water-soluble salts, before, during or after the shaping step. This kind of process is preferably used in the production of oxidation catalysts supported by titanium silicate or vanadium silicate carriers with a zeolite structure, and the prepared catalyst can contain 0.01 to 30 wt% of one or more selected from ruthenium, rhodium, palladium, Precious metals of osmium, iridium, platinum, rhenium, gold and silver. Such catalysts are described, for example, in DE-A 19623609.6, to which reference is hereby made in its entirety with respect to the catalysts.

In many cases, however, it is most convenient to load the precious metal component onto the shaped body only after the shaping step has been completed, especially when it is not desired to subject the noble metal containing catalyst to high temperatures. The precious metal component can be loaded onto the shaped body specifically by means of ion exchange, impregnation or spraying. This loading can be carried out with organic solvents, aqueous ammonia or supercritical phases such as carbon dioxide.

The adoption of the above method makes it possible to prepare various noble metal-containing catalysts. For example, coated catalysts can be prepared by spraying a noble metal solution onto shaped bodies. The thickness of the coating or the noble metal-containing shell can be increased considerably by impregnation, whereas in the case of ion exchange the catalyst particles will be loaded with the noble metal substantially uniformly along the entire cross-section of the shaped body.

After being extruded from a piston extruder or a screw extruder, the shaped body obtained is usually dried at 50 to 250°C, preferably 80 to 250°C and generally at a pressure of 0.01 to 5bar, preferably 0.05 to 1.5bar, for about 1 ~20h.

The subsequent calcination is carried out at 250-800°C, preferably 350-600°C, especially preferably 400-500°C. The pressure used is similar to that used for drying. Generally, the calcination is carried out in an oxygen-containing atmosphere, wherein the oxygen content is 0.1-90% (volume), preferably 0.2-22% (volume), especially preferably 0.2-10% (volume).

Accordingly, the present invention also provides a method for producing the above-mentioned shaped body, which comprises the following steps (i) to (v):

(i) one or more porous oxide materials are mixed with at least one metal oxide sol low in alkali metal and alkaline earth metal ions and/or at least one metal oxide low in alkali metal and alkaline earth metal ions;

(ii) compacting the mixture from step (i), adding a metal oxide sol if desired;

(iii) shaping the composition from step (ii);

(iv) drying the shaped body from step (iii);

(v) The dried shaped body from step (iv) is calcined.

In a particular embodiment of the invention, the metal oxide sol is added to the suspension obtained from step (b) described above, the suspension formed is dried, preferably by spray drying, and the formed The powder is calcined. The dried and calcined product can then be further processed according to step (iii).

Of course, the extrudates obtained can also be processed further. Any comminution methods, such as crushing or crushing of shaped bodies, are also conceivable, as are further chemical treatments, for example as described above. If comminution is carried out, pellets or chips are preferably produced with a particle diameter of 0.1 to 5 mm, especially 0.5 to 2 mm.

The pellets or chips as well as otherwise produced shaped bodies contain practically no finer particles with a minimum particle diameter of about 0.1 mm.

The shaped bodies according to the invention or produced according to the invention can be used as catalysts, in particular for catalytic conversions, especially for the oxidation of organic molecules. Examples of possible responses are:

Olefin epoxidation, such as the preparation of propylene oxide from mixtures of propylene and hydrogen peroxide or from propylene and in situ hydrogen peroxide;

Hydroxylation, such as the hydroxylation of monocyclic, bicyclic or polycyclic aromatic hydrocarbons to mono-, di- or higher-substituted hydroxyaromatic hydrocarbons, such as the reaction of phenol with hydrogen peroxide or a mixture of phenol and hydrogen peroxide generated in situ to produce hydrogen quinone;

Conversion of alkanes to alcohols, aldehydes and acids;

Ketones generate oximes (ammonoximation (ammonoximation)) in the presence of hydrogen peroxide or a mixture capable of generating hydrogen peroxide in situ and ammonia, for example the preparation of cyclohexanone oxime from cyclohexanone;

Isomerization reactions, such as the conversion of epoxides to aldehydes;

And there are also reactions described in the literature as being catalyzed by such shaped bodies, especially zeolite catalysts, as described for example in WH In Iderich, "Zeolites: Catalysts for the Synthesis of Organic Compounds", Elsevier, Surface Science Research. Catalysis 49, Amsterdam (1989), pp. 69-93; and, in particular, possible oxidation reactions, eg B. Notari in Surface Scientific Research. Catalysis" 37, (1987), pp.413-425 or described in "Progress in Catalysis", Volume 41, Academic Press (1996), pp.253-334.

The invention therefore provides the use of one of the shaped bodies prepared as described above or a mixture of 2 or more thereof as a catalyst.

The zeolites discussed more fully above are especially suitable for the epoxidation of alkenes.

Accordingly, the present invention also provides a method for preparing at least one alkylene oxide, which comprises the following step (III):

(III) The reaction of at least one alkene with hydrogen peroxide is carried out using the shaped body produced as described above or the shaped body described above as a catalyst.

Alkenes which may be functionalized by such epoxidation are, for example, ethylene, propylene, 1-butene, 2-butene, isobutene, butadiene, pentene, piperylene, hexene, hexadiene , heptene, octene, diisobutene, trimethylpentene, nonene, dodecene, tridecene, tetra-~eicosene, tri- and tetrapropylene, polybutadiene, polyisobutene , isoprene, terpene, geraniol, linalool, linalyl acetate, methylenecyclopropane, cyclopentene, cyclohexene, norbornene, cycloheptene, vinylcyclohexane, Vinyl oxirane, vinyl cyclohexene, styrene, cyclooctene, cyclooctadiene, vinyl norbornene, indene, tetrahydroindene, methylstyrene, dicyclopentadiene, divinyl Benzene, cyclododecene, cyclododecatriene, stilbene, diphenylbutadiene, vitamin A, β-carotene, vinylidene fluoride, allyl halide, crotyl chloride , Methallyl Chloride, Dichlorobutene, Allyl Alcohol, Methallyl Alcohol, Butenyl Alcohol, Butenediol, Cyclopentenediol, Pentenyl Alcohol, Octadienyl Alcohol, Tridecyl Alcohol Enols, unsaturated steroids, ethoxylated ethylene, isoeugenol, anethole, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, vinylacetic acid, unsaturated fatty acids such as oleic acid , linoleic acid, palmitic acid, naturally occurring fats and oils.

The zeolites discussed extensively above are especially suitable for the epoxidation of alkenes of 2 to 8 carbon atoms, more preferably ethylene, propylene or butenes, especially propylene, resulting in the corresponding alkylene oxides.

Accordingly, the invention provides in particular the use of the shaped bodies described herein as catalysts for the preparation of propylene oxide starting from propylene and hydrogen peroxide or from mixtures of propylene and hydrogen peroxide capable of being generated in situ.

In a particular embodiment of the process, the alkene to be epoxidized is prepared by dehydrogenation of the corresponding alkane.

Accordingly, the present invention also provides a method as described above, which includes additional steps (1):

(I) One or more alkenes reacted in step (III) are prepared by dehydrogenation of at least one alkane.

The dehydrogenation reaction can in principle be carried out by any method known from the prior art. Such methods are described inter alia in EP-A 0850 936, the contents of which are incorporated herein by reference in their entirety.

In a preferred embodiment of the process of the present invention, the hydrogen produced by the dehydrogenation of one or more alkanes is used to prepare a process which reacts with the one or more alkenes produced after dehydrogenation in reaction step (III). hydrogen oxide.

Accordingly, the present invention also provides a method as described above, which includes the following steps (II):

(II) The hydrogen generated in the step (I) reacts to generate hydrogen peroxide, wherein the hydrogen peroxide is used in the reaction of the step (III) again.

Accordingly, the present invention also provides a combined method for preparing oxyalkylene, which includes steps (A) to (C):

(A) dehydrogenation of alkanes to alkenes and hydrogen,

(B) reacting the hydrogen obtained from (A) to generate hydrogen peroxide, and

(C) The hydrogen peroxide obtained from (B) is reacted with the alkene obtained from (A) with the aid of the shaped bodies of the process according to the invention to give alkylene oxides.

The reaction of hydrogen to generate hydrogen peroxide can be carried out by any method known in the prior art. In particular, the hydrogen reacts with molecular oxygen to form hydrogen peroxide. It is likewise conceivable to prepare hydrogen peroxide by the anthraquinone process using the hydrogen from step (A). In both cases, the hydrogen from step (A) may need to be purified before reuse. However, the anthraquinone method is preferred. The method is based on the catalytic hydrogenation of an anthraquinone compound to the corresponding anthrahydroquinone compound, which is then reacted with oxygen to form hydrogen peroxide, which is subsequently isolated by extraction. The catalytic cycle is closed by the rehydrogenation of the anthraquinone compound obtained in the previous reaction with oxygen. An overview of the anthraquinone method is contained in "Ullmann Encyclopedia of Industrial Chemistry", Fifth Edition, Volume 13, pp.447-456.

During the use of one or more shaped bodies according to the invention as catalysts, the latter can be regenerated when deactivated by local charring of the deposits which caused the deactivation. This is preferably carried out in an inert gas atmosphere containing precisely defined amounts of oxygen source species. This regeneration method is described in DE-A 197 23 949.8, the relevant content of which is incorporated herein by reference in its entirety.

Furthermore, the invention provides in its most general embodiment the use of a metal oxide sol prepared as described above as a binder for the production of shaped bodies having high chemical resistance and high mechanical strength.

Detailed ways

The following examples illustrate the invention.

Example

Example 1: Preparation of microporous oxide material

910 g of tetraethyl orthosilicate was put into a four-necked flask (4 L capacity), and 15 g of tetraisopropyl orthotitanate was added from the dropping funnel under stirring (250 rpm, paddle stirrer) within 30 minutes. A colorless, transparent mixture was formed. Subsequently, 1600 g of a 20% by weight tetrapropylammonium hydroxide solution (with an alkali metal content of less than 10 ppm) was added, and the mixture was stirred for another 1 h. The alcohol mixture (about 900 g) produced by hydrolysis was distilled off at 90-100°C. 3 L of water was added, at which point the slightly opaque sol was transferred to a 5 L capacity stainless steel stirred autoclave.

A sealed autoclave (anchor stirrer, 200 rpm) was heated to a reaction temperature of 175°C at a heating rate of 3°C/min. The reaction was complete after 92h. The cooled reaction mixture (white suspension) was centrifuged and the solid was washed several times with water until neutral. The obtained solid was dried at 110° C. for 24 h (weight: 298 g). The template remaining in the zeolite was subsequently removed during calcination in air at 550° C. for 5 h (loss on calcination: 14 wt %).

The white pure product had, according to wet chemical analysis, a titanium content of 1.5% by weight and a residual alkali metal content of less than 100 ppm. The yield based on the amount of silica used was 97%. The crystal size ranges from 0.05 to 0.25 μm, and the product shows a typical band around 960 cm-1 in the infrared spectrum.

Example 2: Preparation of silica sol

3L of water was added to a 10L four-necked flask equipped with a stirrer, thermometer and reflux condenser. The pH value of the solution was adjusted to 8-9 with 6 g of 25% ammonia. Subsequently, the water was heated to 50° C., and then 1300 g of tetraethyl orthosilicate was added from the dropping funnel.

The mixture of water and tetraethyl orthosilicate was refluxed for 3h. Then, a further 1304 g of tetraethyl orthosilicate was added through the dropping funnel. After refluxing for another 2 h, the resulting silica sol/water mixture was stirred for a further 12 h, and then the ethanol formed by hydrolysis was distilled off.

3618 g of the silica sol thus prepared contained about 20 wt% silica and less than 3 ppm alkali metal ions.

Example 3: Preparation of silica sol

188.6g of water was added to a 500mL four-necked flask equipped with a stirrer, a thermometer and a reflux condenser. The pH of the solution was adjusted to 9 with 0.3 g of 25% strength ammonia. Subsequently, the water was heated to 50° C. and 111.65 g of tetraethylorthosilicate were added from the dropping funnel.

The mixture of water and tetraethyl orthosilicate was refluxed for 2h. Then, an additional 111.65 g of tetraethylorthosilicate was added through the dropping funnel. After a further 2 h of reflux, the resulting silica sol/water mixture was refluxed for a further 12 h. 50 g of water were then added, and the ethanol formed by the hydrolysis was then distilled off.

169 g of the silica sol thus prepared contained about 38 wt% silica and less than 5 ppm alkali metal ions.

Example 4: Spray of titanium silicate

200 g of ground catalyst prepared as described in Example 1 were first finely ground to a particle size of less than 300 μm and then suspended in 2000 g of water. Then 245 g of a silica hydrosol having a silica content of 18% by weight prepared as described in Example 2 were mixed in.

Under the condition of continuous stirring, the suspension is pressed into the glass-made laboratory spray dryer (diameter: 200mm, height of cylindrical part: 500mm) by a peristaltic pump, and passed through a two-phase flow nozzle (liquid feeding line diameter: 2.5mm; nozzle gas inlet pressure: 3bar) and atomized.

In the spray dryer, the suspension is dried by drying gas (nitrogen, throughput: 24 kg/h, inlet temperature: 210 °C; outlet temperature: 100 °C) to form an intimately mixed powder, subsequently, in a glass cyclone separate from. The yield was 80%.

Example 5: Spray of titanium silicate

16.1 kg of catalyst prepared as described in Example 1 were first coarsely ground in a hammer mill and then finely ground to a particle size of less than 300 μm using an impeller crusher.

Subsequently, the powder was suspended in 160 L of water, 16 kg of a silica hydrosol with a silica content of 20 wt % prepared as described in Example 2 was added, and then put into an open stirring vessel. Under constant stirring conditions, the suspension was sucked out by a large peristaltic pump and dried in a spray drying unit (manufactured by Niro Corporation) to form a fine, intimately mixed powder.

The suspension was micronized using a disc atomizer (rotational speed: 17,000 rpm) equipped with a ceramic liner. Drying was carried out at an air inlet temperature of 260°C and an air outlet temperature of 110°C.

The product is separated from the air stream in a cyclone. The yield was 13 kg.

Comparative Example 1: Forming of titanium silicate (catalyst A)

Catalyst A was passed between 1665 g of a spray-dried powder consisting of 89% by weight of the catalyst prepared as described in Example 1 and 11% by weight of silica, and 416 g of silica sol (Ludox™, manufactured by DuPont) with a silica content of about 50% by weight. made of a mix. The specified spray-dried powder was prepared analogously to Example 4, except that the silica sol prepared according to the invention was replaced by industrially produced silica sol with a sodium content of 800 ppm (Ludox AS-40, manufactured by DuPont).

The mixture was rendered extrudable by adding water and the extrusion aid methylcellulose and extruded into extrudates with a diameter of 1.5 mm.

The extrudate was dried at 120°C and then heated at 500°C for 5h. The silica binder content of the shaped body was 20% by weight; the sodium content, 700 ppm.

Comparative Example 2: Forming of Titanium Silicate (Catalyst B)

Catalyst B is passed through 3000g by 78wt% by 78wt% the spray-dried powder that the catalyst that prepares as described in example 1 and 22wt% silicon dioxide form, and the silica sol (Ludox AS-40 of Du Pont Company manufacture) of about 43wt% of silicon dioxide content with 750g Mixtures in between.

The specified spray-dried powder was prepared analogously to Example 4, except that the silica sol prepared according to the invention was replaced by industrially produced silica sol with a sodium content of 800 ppm (Ludox AS-40, manufactured by DuPont).

The mixture was rendered extrudable by adding water and the extrusion aid methylcellulose and extruded into extrudates with a diameter of 2.5 mm.

The extrudate was dried at 120°C and then heated at 500°C for 5h. The silica binder content of the shaped body was 30% by weight; the sodium content, 910 ppm. The transverse compressive strength of the extrudate is 37.9N; the cut resistance is 10.25N.

Comparative Example 3: Forming of Titanium Silicate (Catalyst C)

Catalyst C is passed through 7500g by 78wt% by 78wt% the spray-dried powder that the catalyst of preparing as described in example 1 and 22wt% silicon dioxide form, and the silica sol (Ludox AS-40 of Du Pont Company manufacture) of about 43wt% of silicon dioxide content with 4300g Made by mixing in a disc mill.

The specified spray-dried powder was prepared according to Example 4, except that the silica sol prepared according to the invention was replaced by industrially produced silica sol with a sodium content of 800 ppm (Ludox AS-40, manufactured by DuPont).

The mixture was rendered extrudable by adding water and the extrusion aid methylcellulose and extruded into extrudates with a diameter of 1.5 mm.

The extrudate was dried at 120°C and then heated at 500°C for 5h. The silica binder content of the shaped body was 30% by weight; the sodium content, 900 ppm.

Example 6: Formation of titanium silicate (catalyst D)

Catalyst D was prepared by 2200g of the catalyst prepared as described in Example 1 and the spray-dried powder of 25wt% silica, and 1037g of silica sol with a silica content of about 21wt% prepared as described in Example 2 Mix made. The specified spray-dried powder was prepared in a manner similar to Example 4.

The mixture was rendered extrudable by adding water and the extrusion aid methylcellulose and extruded into extrudates with a diameter of 1.5 mm.

The extrudate was dried at 120°C and then heated at 500°C for 5h. The silica binder content of the shaped body was 32% by weight; the sodium content, 400 ppm.

Example 7: Formation of titanium silicate (catalyst E)

Catalyst E is passed through 9700g by 75wt% by the spray-dried powder that the catalyst that prepares as described in example 1 and 25wt% silicon dioxide and 13000g prepares as described in example 2 The silica sol of silicon dioxide content about 19wt% in disc mill Made by mixing.

The specified spray-dried powder was prepared in a manner similar to Example 4.

The mixture was rendered extrudable by adding water and the extrusion aid methylcellulose and extruded into extrudates with a diameter of 1.5 mm.

The extrudate was dried at 120°C and then heated at 500°C for 5h. The silica binder content of the shaped body was 40% by weight; the sodium content, 420 ppm.

Example 8: Formation of titanium silicate (catalyst F)

Catalyst F is passed through 8000g by 70wt% by the spray-dried powder that the catalyst that prepares as described in example 1 and 30wt% silicon dioxide form, and the silica sol that 4000g prepares as described in example 2 has a silicon dioxide content of about 19wt% in the pan Made by mixing in the mill.

The specified spray-dried powder was prepared in a manner similar to Example 4.

The mixture was rendered extrudable by adding water and the extrusion aid methylcellulose and extruded into extrudates with a diameter of 1.5 mm.

The extrudate was dried at 120°C and then heated at 500°C for 5h. The silica binder content of the shaped body was 40% by weight; the sodium content, 400 ppm. Cut resistance is 2N; transverse compressive strength, 19N.

Example 9: Compaction and Forming of Titanium Silicate (Catalyst G)

(DEGUSSA)、6.26kg如实例2所述制备的硅溶胶及237g甲基纤维素(

)一起压实60min。3.5 kg of TS-1 prepared as described in Example 1 was mixed with 1.23 kg in a disc mill

(DEGUSSA), 6.26kg of silica sol prepared as described in Example 2 and 237g of methyl cellulose (

) compacted together for 60 minutes.

)，混合物再压实30min，加入96g聚乙二醇()及450g去离子水，然后混合物再次压实15min。Subsequently, add 48g polyethylene glycol (

), the mixture was compacted for 30min, and 96g polyethylene glycol was added ( ) and 450g deionized water, and then the mixture was compacted again for 15min.

The extrudable composition was formed into 1.5 mm round extrudates using an extruder. The extrusion pressure ranges from 85 to 100 bar; the extrusion time is 15 minutes. The extrudates were dried at 120° C. and calcined in air at 500° C. for 5 h.

The yield was 5.1 kg. The silicon dioxide binder content of the molded body is 40wt%; the sodium content is 500ppm; the transverse compressive strength is 17N; the macropore volume, measured according to the mercury pore determination method stipulated in DIN66133, is 0.70g/ml.

Example 10: Catalytic Test (Batch Operation)

In each case, an amount corresponding to 0.5 g of the mass of titanium silicate of catalysts A to G was charged into a steel autoclave equipped with basket-shaped internals and bubbling stirrer.

Add 100 g of methanol to the autoclave, seal it and check for leaks. Subsequently, the autoclave was heated to 40° C., and 11 g of liquid propylene were metered into the autoclave.

Subsequently, 9.0 g of 30 wt % hydrogen peroxide aqueous solution was pressed into the autoclave by using an HPLC (high pressure liquid chromatography) pump, and then 16 mL of methanol was used to flush the residual hydrogen peroxide in the feed line into the autoclave. The initial hydrogen peroxide content in the reaction solution was 2.5 wt%.

After 2 h reaction time, the autoclave was cooled and vented. The content of hydrogen peroxide in the liquid product was analyzed by cerium titration. The propylene oxide content of the product was determined by gas chromatography.

The results of the analysis are summarized in the table below.

Table: Example 10 (catalytic test)

catalyst Propylene oxide content in the product, wt% Hydrogen peroxide content in the product, wt% A (comparative example) 0,88 1,72 B (comparative example) 0,86 1,74 C (comparative example) 0,93 1,51 D. 1,39 1, 28 E. 1,47 1, 19 f 1,34 1, 25 G 1,1 1,45

Example 11: Catalytic test (continuous operation)

24g/h hydrogen peroxide (40wt%), 57g/h methanol and 11.7ml/h propylene passed through the tubular reactor equipped with 28.1g catalyst F of the present invention at a reaction temperature of 40°C and a pressure of 20 bar.

After leaving the reactor, the reaction mixture was decompressed to atmospheric pressure in a Sambay evaporator. The separated low boiling points were analyzed by an online gas chromatograph. The liquid reaction product was collected, weighed and analyzed similarly by gas chromatography.

The total reaction time is 550h. During this period, the hydrogen peroxide conversion was well above 90%. The selectivity of hydrogen peroxide to propylene oxide was also significantly higher than 90% over the entire test period.

Example 12: Catalytic test (continuous operation)

9g/h hydrogen peroxide (40wt%), 49g/h methanol and 8g/h propylene passed through the tubular reactor equipped with 20g of the catalyst G of the present invention at a reaction temperature of 40°C and a pressure of 20bar.

After leaving the reactor, the reaction mixture was decompressed to atmospheric pressure in a Sambay evaporator. The separated low boiling points were analyzed by an online gas chromatograph. The liquid reaction product was collected, weighed and analyzed similarly by gas chromatography.

The total reaction time is 850h. During this period, the hydrogen peroxide conversion was well above 90%. The selectivity of hydrogen peroxide to propylene oxide was also significantly higher than 90% over the entire test period.

Claims (10)

1. the alkali metal that contains and the content of alkaline-earth metal ions are lower than the formed body of 500ppm, and it comprises at least a titanium zeolite and at least a metal oxide, described formed body by comprise the following steps (i) to (method v) obtains:

(i) comprise that by spraying the suspended substance of at least a titanium zeolite and metal oxide sol mixes at least a titanium zeolite with at least a metal oxide sol,

(ii) compacting is wherein introduced other metal oxides from the mixture of step (i), adopts metal oxide sol as metal oxide source,

(iii) will be shaped from step composition (ii),

(iv) will be from step formed body drying (iii),

(v) will calcine from the formed body of step drying (iv),

Wherein step (i) and (ii) in the content of the alkalies and alkaline earth ion that contains of the metal oxide sol that uses less than 10ppm.

2. the formed body of claim 1, it is micropore and also has mesopore and macropore in addition that wherein the void content of mesopore and macropore is determined as greater than 0.1ml/g according to DIN 66133 substantially.

3. the alkali metal that contains and the content of alkaline-earth metal ions are lower than the formed body of 500ppm, and it comprises at least a titanium zeolite and at least a oxide, described formed body by comprise the following steps (i) to (method v) obtains:

(i) comprise that by spraying the suspended substance of at least a titanium zeolite and oxide sol mixes at least a titanium zeolite with at least a oxide sol,

(ii) compacting is wherein introduced other oxides from the mixture of step (i), adopts oxide sol as oxide source,

(iii) will be shaped from step composition (ii),

(iv) will be from step formed body drying (iii),

(v) will calcine from the formed body of step drying (iv),

Wherein step (i) and (ii) in the content of the alkalies and alkaline earth ion that contains of the oxide sol that uses less than 10ppm, and

Wherein said oxide is a silica, and described oxide sol is a Ludox.

4. the formed body of claim 3, wherein said titanium zeolite is a titanium silicate.

5. the alkali metal that contains and the content of alkaline-earth metal ions are lower than the formed body of 500ppm or its multiple mixture as Application of Catalyst, described formed body comprises at least a titanium zeolite and at least a metal oxide, described formed body by comprise the following steps (i) to (method v) obtains:

(i) comprise that by spraying the suspended substance of at least a titanium zeolite and metal oxide sol mixes at least a titanium zeolite with at least a metal oxide sol,

(ii) compacting is wherein introduced other metal oxides from the mixture of step (i), adopts metal oxide sol as metal oxide source,

(iii) will be shaped from step composition (ii),

(iv) will be from step formed body drying (iii),

(v) will calcine from the formed body of step drying (iv),

Wherein step (i) and (ii) in the content of the alkalies and alkaline earth ion that contains of the metal oxide sol that uses less than 10ppm.

6. the application of claim 5, described formed body are micropore and also have mesopore and macropore in addition that wherein the void content of mesopore and macropore is determined as greater than 0.1ml/g according to DIN 66133 substantially.

7. the alkali metal that contains and the content of alkaline-earth metal ions are lower than the formed body of 500ppm or its multiple mixture as Application of Catalyst, described formed body comprises at least a titanium zeolite and at least a oxide, described formed body by comprise the following steps (i) to (method v) obtains:

(i) comprise that by spraying the suspended substance of at least a titanium zeolite and oxide sol mixes at least a titanium zeolite with at least a oxide sol,

(ii) compacting is wherein introduced other oxides from the mixture of step (i), adopts oxide sol as oxide source,

(iii) will be shaped from step composition (ii),

(iv) will be from step formed body drying (iii),

(v) will calcine from the formed body of step drying (iv),

Wherein step (i) and (ii) in the content of the alkalies and alkaline earth ion that contains of the oxide sol that uses less than 10ppm, and

Wherein said oxide is a silica, and described oxide sol is a Ludox.

8. the application of claim 7, wherein said titanium zeolite is a titanium silicate.

9. the application of claim 7, wherein said formed body be used as by propylene and hydrogen peroxide or by propylene and the mixture that generates hydrogen peroxide on the spot prepare the catalyst of expoxy propane.

10. the application of claim 8, wherein said formed body be used as by propylene and hydrogen peroxide or by propylene and the mixture that generates hydrogen peroxide on the spot prepare the catalyst of expoxy propane.